The goals of this Microbiology Core are to provide standardized testing in support for Projects 3, and 4 of this program project grant application. Specifically, the Microbiology Core will: (1) support Project 3 by performing in vitro microbiologic assessments of selective active and excipient agents on the viability of Neisseria gonorrhoeae, Trichomonas vaginalis, Chlamydia trachomatis, and Lactobacillus crispatus; (2) perform the microbial challenge studies for assessment of preservation activity in support of formulation development in Project 3; (3) perform safety testing in support of the clinical studies outlined in Project 4, as well as assessments of inflammation and standard STD screening tests. For in vitro testing, the minimal cidal concentration (MCC) assay will be utilized to assess the effects of formulation components on STD pathogens and Lactobacillus, a component of the normal vaginal flora. Finally, clinical studies will be supported by standardized quantitative vaginal cultures for assessment of changes in low- or high-frequency vaginal flora following normal microbicide use. Measures of inflammation will include assessment of neutrophils in the cervical mucus, as well as pro-inflammatory cytokines including IL-1-beta, IL-6, IL-8, and TNF-alpha. These indicators will be added to evaluate different methods for identification of inflammation in women receiving topical microbicides. This core will directly support Projects 3, and 4.